/*-
 * Copyright (c) 2003, 2004, 2005, 2006, 2007 Lev Walkin <vlm@lionet.info>.
 * All rights reserved.
 * Redistribution and modifications are permitted subject to BSD license.
 */
#include <asn_internal.h>
#include <constr_SEQUENCE.h>
#include <per_opentype.h>

/*
 * Number of bytes left for this structure.
 * (ctx->left) indicates the number of bytes _transferred_ for the structure.
 * (size) contains the number of bytes in the buffer passed.
 */
#define LEFT ((size < (size_t)ctx->left) ? size : (size_t)ctx->left)

/*
 * If the subprocessor function returns with an indication that it wants
 * more data, it may well be a fatal decoding problem, because the
 * size is constrained by the <TLV>'s L, even if the buffer size allows
 * reading more data.
 * For example, consider the buffer containing the following TLVs:
 * <T:5><L:1><V> <T:6>...
 * The TLV length clearly indicates that one byte is expected in V, but
 * if the V processor returns with "want more data" even if the buffer
 * contains way more data than the V processor have seen.
 */
#define SIZE_VIOLATION (ctx->left >= 0 && (size_t)ctx->left <= size)

/*
 * This macro "eats" the part of the buffer which is definitely "consumed",
 * i.e. was correctly converted into local representation or rightfully skipped.
 */
#undef ADVANCE
#define ADVANCE(num_bytes)                \
  do {                                    \
    size_t num = num_bytes;               \
    ptr = ((const char *)ptr) + num;      \
    size -= num;                          \
    if (ctx->left >= 0) ctx->left -= num; \
    consumed_myself += num;               \
  } while (0)

/*
 * Switch to the next phase of parsing.
 */
#undef NEXT_PHASE
#undef PHASE_OUT
#define NEXT_PHASE(ctx) \
  do {                  \
    ctx->phase++;       \
    ctx->step = 0;      \
  } while (0)
#define PHASE_OUT(ctx) \
  do {                 \
    ctx->phase = 10;   \
  } while (0)

/*
 * Return a standardized complex structure.
 */
#undef RETURN
#define RETURN(_code)                \
  do {                               \
    rval.code = _code;               \
    rval.consumed = consumed_myself; \
    return rval;                     \
  } while (0)

/*
 * Check whether we are inside the extensions group.
 */
#define IN_EXTENSION_GROUP(specs, memb_idx) \
  (((memb_idx) > (specs)->ext_after) && ((memb_idx) < (specs)->ext_before))

/*
 * Tags are canonically sorted in the tag2element map.
 */
static int _t2e_cmp(const void *ap, const void *bp) {
  const asn_TYPE_tag2member_t *a = (const asn_TYPE_tag2member_t *)ap;
  const asn_TYPE_tag2member_t *b = (const asn_TYPE_tag2member_t *)bp;

  int a_class = BER_TAG_CLASS(a->el_tag);
  int b_class = BER_TAG_CLASS(b->el_tag);

  if (a_class == b_class) {
    ber_tlv_tag_t a_value = BER_TAG_VALUE(a->el_tag);
    ber_tlv_tag_t b_value = BER_TAG_VALUE(b->el_tag);

    if (a_value == b_value) {
      if (a->el_no > b->el_no) return 1;
      /*
       * Important: we do not check
       * for a->el_no <= b->el_no!
       */
      return 0;
    } else if (a_value < b_value)
      return -1;
    else
      return 1;
  } else if (a_class < b_class) {
    return -1;
  } else {
    return 1;
  }
}

/*
 * The decoder of the SEQUENCE type.
 */
asn_dec_rval_t SEQUENCE_decode_ber(asn_codec_ctx_t *opt_codec_ctx,
                                   asn_TYPE_descriptor_t *td, void **struct_ptr,
                                   const void *ptr, size_t size, int tag_mode) {
  /*
   * Bring closer parts of structure description.
   */
  asn_SEQUENCE_specifics_t *specs = (asn_SEQUENCE_specifics_t *)td->specifics;
  asn_TYPE_member_t *elements = td->elements;

  /*
   * Parts of the structure being constructed.
   */
  void *st = *struct_ptr; /* Target structure. */
  asn_struct_ctx_t *ctx;  /* Decoder context */

  ber_tlv_tag_t tlv_tag; /* T from TLV */
  asn_dec_rval_t rval;   /* Return code from subparsers */

  ssize_t consumed_myself = 0; /* Consumed bytes from ptr */
  int edx;                     /* SEQUENCE element's index */

  ASN_DEBUG("Decoding %s as SEQUENCE", td->name);

  /*
   * Create the target structure if it is not present already.
   */
  if (st == 0) {
    st = *struct_ptr = CALLOC(1, specs->struct_size);
    if (st == 0) {
      RETURN(RC_FAIL);
    }
  }

  /*
   * Restore parsing context.
   */
  ctx = (asn_struct_ctx_t *)((char *)st + specs->ctx_offset);

  /*
   * Start to parse where left previously
   */
  switch (ctx->phase) {
    case 0:
      /*
       * PHASE 0.
       * Check that the set of tags associated with given structure
       * perfectly fits our expectations.
       */

      rval = ber_check_tags(opt_codec_ctx, td, ctx, ptr, size, tag_mode, 1,
                            &ctx->left, 0);
      if (rval.code != RC_OK) {
        ASN_DEBUG("%s tagging check failed: %d", td->name, rval.code);
        return rval;
      }

      if (ctx->left >= 0) ctx->left += rval.consumed; /* ?Substracted below! */
      ADVANCE(rval.consumed);

      NEXT_PHASE(ctx);

      ASN_DEBUG("Structure consumes %ld bytes, buffer %ld", (long)ctx->left,
                (long)size);

      /* Fall through */
    case 1:
      /*
       * PHASE 1.
       * From the place where we've left it previously,
       * try to decode the next member from the list of
       * this structure's elements.
       * (ctx->step) stores the member being processed
       * between invocations and the microphase {0,1} of parsing
       * that member:
       * 	step = (<member_number> * 2 + <microphase>).
       */
      for (edx = (ctx->step >> 1); edx < td->elements_count;
           edx++, ctx->step = (ctx->step & ~1) + 2) {
        void *memb_ptr;   /* Pointer to the member */
        void **memb_ptr2; /* Pointer to that pointer */
        ssize_t tag_len;  /* Length of TLV's T */
        int opt_edx_end;  /* Next non-optional element */
        int use_bsearch;
        int n;

        if (ctx->step & 1) goto microphase2;

        /*
         * MICROPHASE 1: Synchronize decoding.
         */
        ASN_DEBUG(
            "In %s SEQUENCE left %d, edx=%d flags=%d"
            " opt=%d ec=%d",
            td->name, (int)ctx->left, edx, elements[edx].flags,
            elements[edx].optional, td->elements_count);

        if (ctx->left == 0 /* No more stuff is expected */
            && (
                   /* Explicit OPTIONAL specification reaches the end */
                   (edx + elements[edx].optional == td->elements_count) ||
                   /* All extensions are optional */
                   (IN_EXTENSION_GROUP(specs, edx) &&
                    specs->ext_before > td->elements_count))) {
          ASN_DEBUG("End of SEQUENCE %s", td->name);
          /*
           * Found the legitimate end of the structure.
           */
          PHASE_OUT(ctx);
          RETURN(RC_OK);
        }

        /*
         * Fetch the T from TLV.
         */
        tag_len = ber_fetch_tag(ptr, LEFT, &tlv_tag);
        ASN_DEBUG(
            "Current tag in %s SEQUENCE for element %d "
            "(%s) is %s encoded in %d bytes, of frame %ld",
            td->name, edx, elements[edx].name, ber_tlv_tag_string(tlv_tag),
            (int)tag_len, (long)LEFT);
        switch (tag_len) {
          case 0:
            if (!SIZE_VIOLATION) RETURN(RC_WMORE);
            /* Fall through */
          case -1:
            RETURN(RC_FAIL);
        }

        if (ctx->left < 0 && ((const uint8_t *)ptr)[0] == 0) {
          if (LEFT < 2) {
            if (SIZE_VIOLATION)
              RETURN(RC_FAIL);
            else
              RETURN(RC_WMORE);
          } else if (((const uint8_t *)ptr)[1] == 0) {
            ASN_DEBUG("edx = %d, opt = %d, ec=%d", edx, elements[edx].optional,
                      td->elements_count);
            if ((edx + elements[edx].optional == td->elements_count) ||
                (IN_EXTENSION_GROUP(specs, edx) &&
                 specs->ext_before > td->elements_count)) {
              /*
               * Yeah, baby! Found the terminator
               * of the indefinite length structure.
               */
              /*
               * Proceed to the canonical
               * finalization function.
               * No advancing is necessary.
               */
              goto phase3;
            }
          }
        }

        /*
         * Find the next available type with this tag.
         */
        use_bsearch = 0;
        opt_edx_end = edx + elements[edx].optional + 1;
        if (opt_edx_end > td->elements_count)
          opt_edx_end = td->elements_count; /* Cap */
        else if (opt_edx_end - edx > 8) {
          /* Limit the scope of linear search... */
          opt_edx_end = edx + 8;
          use_bsearch = 1;
          /* ... and resort to bsearch() */
        }
        for (n = edx; n < opt_edx_end; n++) {
          if (BER_TAGS_EQUAL(tlv_tag, elements[n].tag)) {
            /*
             * Found element corresponding to the tag
             * being looked at.
             * Reposition over the right element.
             */
            edx = n;
            ctx->step = 1 + 2 * edx; /* Remember! */
            goto microphase2;
          } else if (elements[n].flags & ATF_OPEN_TYPE) {
            /*
             * This is the ANY type, which may bear
             * any flag whatsoever.
             */
            edx = n;
            ctx->step = 1 + 2 * edx; /* Remember! */
            goto microphase2;
          } else if (elements[n].tag == (ber_tlv_tag_t)-1) {
            use_bsearch = 1;
            break;
          }
        }
        if (use_bsearch) {
          /*
           * Resort to a binary search over
           * sorted array of tags.
           */
          asn_TYPE_tag2member_t *t2m;
          asn_TYPE_tag2member_t key;
          key.el_tag = tlv_tag;
          key.el_no = edx;
          t2m = (asn_TYPE_tag2member_t *)bsearch(
              &key, specs->tag2el, specs->tag2el_count,
              sizeof(specs->tag2el[0]), _t2e_cmp);
          if (t2m) {
            asn_TYPE_tag2member_t *best = 0;
            asn_TYPE_tag2member_t *t2m_f, *t2m_l;
            int edx_max = edx + elements[edx].optional;
            /*
             * Rewind to the first element with that tag,
             * `cause bsearch() does not guarantee order.
             */
            t2m_f = t2m + t2m->toff_first;
            t2m_l = t2m + t2m->toff_last;
            for (t2m = t2m_f; t2m <= t2m_l; t2m++) {
              if (t2m->el_no > edx_max) break;
              if (t2m->el_no < edx) continue;
              best = t2m;
            }
            if (best) {
              edx = best->el_no;
              ctx->step = 1 + 2 * edx;
              goto microphase2;
            }
          }
          n = opt_edx_end;
        }
        if (n == opt_edx_end) {
          /*
           * If tag is unknown, it may be either
           * an unknown (thus, incorrect) tag,
           * or an extension (...),
           * or an end of the indefinite-length structure.
           */
          if (!IN_EXTENSION_GROUP(specs, edx + elements[edx].optional)) {
            ASN_DEBUG("Unexpected tag %s (at %d)", ber_tlv_tag_string(tlv_tag),
                      edx);
            ASN_DEBUG("Expected tag %s (%s)%s",
                      ber_tlv_tag_string(elements[edx].tag), elements[edx].name,
                      elements[edx].optional ? " or alternatives" : "");
            RETURN(RC_FAIL);
          } else {
            /* Skip this tag */
            ssize_t skip;
            edx += elements[edx].optional;

            ASN_DEBUG("Skipping unexpected %s (at %d)",
                      ber_tlv_tag_string(tlv_tag), edx);
            skip = ber_skip_length(opt_codec_ctx, BER_TLV_CONSTRUCTED(ptr),
                                   (const char *)ptr + tag_len, LEFT - tag_len);
            ASN_DEBUG("Skip length %d in %s", (int)skip, td->name);
            switch (skip) {
              case 0:
                if (!SIZE_VIOLATION) RETURN(RC_WMORE);
                /* Fall through */
              case -1:
                RETURN(RC_FAIL);
            }

            ADVANCE(skip + tag_len);
            ctx->step -= 2;
            edx--;
            continue; /* Try again with the next tag */
          }
        }

        /*
         * MICROPHASE 2: Invoke the member-specific decoder.
         */
        ctx->step |= 1; /* Confirm entering next microphase */
      microphase2:
        ASN_DEBUG("Inside SEQUENCE %s MF2", td->name);

        /*
         * Compute the position of the member inside a structure,
         * and also a type of containment (it may be contained
         * as pointer or using inline inclusion).
         */
        if (elements[edx].flags & ATF_POINTER) {
          /* Member is a pointer to another structure */
          memb_ptr2 = (void **)((char *)st + elements[edx].memb_offset);
        } else {
          /*
           * A pointer to a pointer
           * holding the start of the structure
           */
          memb_ptr = (char *)st + elements[edx].memb_offset;
          memb_ptr2 = &memb_ptr;
        }
        /*
         * Invoke the member fetch routine according to member's type
         */
        rval = elements[edx].type->ber_decoder(
            opt_codec_ctx, elements[edx].type, memb_ptr2, ptr, LEFT,
            elements[edx].tag_mode);
        ASN_DEBUG(
            "In %s SEQUENCE decoded %d %s of %d "
            "in %d bytes rval.code %d, size=%d",
            td->name, edx, elements[edx].type->name, (int)LEFT,
            (int)rval.consumed, rval.code, (int)size);
        switch (rval.code) {
          case RC_OK:
            break;
          case RC_WMORE: /* More data expected */
            if (!SIZE_VIOLATION) {
              ADVANCE(rval.consumed);
              RETURN(RC_WMORE);
            }
            ASN_DEBUG("Size violation (c->l=%ld <= s=%ld)", (long)ctx->left,
                      (long)size);
            /* Fall through */
          case RC_FAIL: /* Fatal error */
            RETURN(RC_FAIL);
        } /* switch(rval) */

        ADVANCE(rval.consumed);
      } /* for(all structure members) */

    phase3:
      ctx->phase = 3;
    case 3: /* 00 and other tags expected */
    case 4: /* only 00's expected */

      ASN_DEBUG("SEQUENCE %s Leftover: %ld, size = %ld", td->name,
                (long)ctx->left, (long)size);

      /*
       * Skip everything until the end of the SEQUENCE.
       */
      while (ctx->left) {
        ssize_t tl, ll;

        tl = ber_fetch_tag(ptr, LEFT, &tlv_tag);
        switch (tl) {
          case 0:
            if (!SIZE_VIOLATION) RETURN(RC_WMORE);
            /* Fall through */
          case -1:
            RETURN(RC_FAIL);
        }

        /*
         * If expected <0><0>...
         */
        if (ctx->left < 0 && ((const uint8_t *)ptr)[0] == 0) {
          if (LEFT < 2) {
            if (SIZE_VIOLATION)
              RETURN(RC_FAIL);
            else
              RETURN(RC_WMORE);
          } else if (((const uint8_t *)ptr)[1] == 0) {
            /*
             * Correctly finished with <0><0>.
             */
            ADVANCE(2);
            ctx->left++;
            ctx->phase = 4;
            continue;
          }
        }

        if (!IN_EXTENSION_GROUP(specs, td->elements_count) || ctx->phase == 4) {
          ASN_DEBUG(
              "Unexpected continuation "
              "of a non-extensible type "
              "%s (SEQUENCE): %s",
              td->name, ber_tlv_tag_string(tlv_tag));
          RETURN(RC_FAIL);
        }

        ll = ber_skip_length(opt_codec_ctx, BER_TLV_CONSTRUCTED(ptr),
                             (const char *)ptr + tl, LEFT - tl);
        switch (ll) {
          case 0:
            if (!SIZE_VIOLATION) RETURN(RC_WMORE);
            /* Fall through */
          case -1:
            RETURN(RC_FAIL);
        }

        ADVANCE(tl + ll);
      }

      PHASE_OUT(ctx);
  }

  RETURN(RC_OK);
}

/*
 * The DER encoder of the SEQUENCE type.
 */
asn_enc_rval_t SEQUENCE_encode_der(asn_TYPE_descriptor_t *td, void *sptr,
                                   int tag_mode, ber_tlv_tag_t tag,
                                   asn_app_consume_bytes_f *cb, void *app_key) {
  size_t computed_size = 0;
  asn_enc_rval_t erval;
  ssize_t ret;
  int edx;

  ASN_DEBUG("%s %s as SEQUENCE", cb ? "Encoding" : "Estimating", td->name);

  /*
   * Gather the length of the underlying members sequence.
   */
  for (edx = 0; edx < td->elements_count; edx++) {
    asn_TYPE_member_t *elm = &td->elements[edx];
    void *memb_ptr;
    if (elm->flags & ATF_POINTER) {
      memb_ptr = *(void **)((char *)sptr + elm->memb_offset);
      if (!memb_ptr) {
        if (elm->optional) continue;
        /* Mandatory element is missing */
        _ASN_ENCODE_FAILED;
      }
    } else {
      memb_ptr = (void *)((char *)sptr + elm->memb_offset);
    }
    erval = elm->type->der_encoder(elm->type, memb_ptr, elm->tag_mode, elm->tag,
                                   0, 0);
    if (erval.encoded == -1) return erval;
    computed_size += erval.encoded;
    ASN_DEBUG("Member %d %s estimated %ld bytes", edx, elm->name,
              (long)erval.encoded);
  }

  /*
   * Encode the TLV for the sequence itself.
   */
  ret = der_write_tags(td, computed_size, tag_mode, 1, tag, cb, app_key);
  ASN_DEBUG("Wrote tags: %ld (+%ld)", (long)ret, (long)computed_size);
  if (ret == -1) _ASN_ENCODE_FAILED;
  erval.encoded = computed_size + ret;

  if (!cb) _ASN_ENCODED_OK(erval);

  /*
   * Encode all members.
   */
  for (edx = 0; edx < td->elements_count; edx++) {
    asn_TYPE_member_t *elm = &td->elements[edx];
    asn_enc_rval_t tmperval;
    void *memb_ptr;

    if (elm->flags & ATF_POINTER) {
      memb_ptr = *(void **)((char *)sptr + elm->memb_offset);
      if (!memb_ptr) continue;
    } else {
      memb_ptr = (void *)((char *)sptr + elm->memb_offset);
    }
    tmperval = elm->type->der_encoder(elm->type, memb_ptr, elm->tag_mode,
                                      elm->tag, cb, app_key);
    if (tmperval.encoded == -1) return tmperval;
    computed_size -= tmperval.encoded;
    ASN_DEBUG("Member %d %s of SEQUENCE %s encoded in %ld bytes", edx,
              elm->name, td->name, (long)tmperval.encoded);
  }

  if (computed_size != 0)
    /*
     * Encoded size is not equal to the computed size.
     */
    _ASN_ENCODE_FAILED;

  _ASN_ENCODED_OK(erval);
}

#undef XER_ADVANCE
#define XER_ADVANCE(num_bytes)               \
  do {                                       \
    size_t num = num_bytes;                  \
    buf_ptr = ((const char *)buf_ptr) + num; \
    size -= num;                             \
    consumed_myself += num;                  \
  } while (0)

/*
 * Decode the XER (XML) data.
 */
asn_dec_rval_t SEQUENCE_decode_xer(asn_codec_ctx_t *opt_codec_ctx,
                                   asn_TYPE_descriptor_t *td, void **struct_ptr,
                                   const char *opt_mname, const void *buf_ptr,
                                   size_t size) {
  /*
   * Bring closer parts of structure description.
   */
  asn_SEQUENCE_specifics_t *specs = (asn_SEQUENCE_specifics_t *)td->specifics;
  asn_TYPE_member_t *elements = td->elements;
  const char *xml_tag = opt_mname ? opt_mname : td->xml_tag;

  /*
   * ... and parts of the structure being constructed.
   */
  void *st = *struct_ptr; /* Target structure. */
  asn_struct_ctx_t *ctx;  /* Decoder context */

  asn_dec_rval_t rval;         /* Return value from a decoder */
  ssize_t consumed_myself = 0; /* Consumed bytes from ptr */
  int edx;                     /* Element index */
  int edx_end;

  /*
   * Create the target structure if it is not present already.
   */
  if (st == 0) {
    st = *struct_ptr = CALLOC(1, specs->struct_size);
    if (st == 0) RETURN(RC_FAIL);
  }

  /*
   * Restore parsing context.
   */
  ctx = (asn_struct_ctx_t *)((char *)st + specs->ctx_offset);

  /*
   * Phases of XER/XML processing:
   * Phase 0: Check that the opening tag matches our expectations.
   * Phase 1: Processing body and reacting on closing tag.
   * Phase 2: Processing inner type.
   * Phase 3: Skipping unknown extensions.
   * Phase 4: PHASED OUT
   */
  for (edx = ctx->step; ctx->phase <= 3;) {
    pxer_chunk_type_e ch_type; /* XER chunk type */
    ssize_t ch_size;           /* Chunk size */
    xer_check_tag_e tcv;       /* Tag check value */
    asn_TYPE_member_t *elm;
    int n;

    /*
     * Go inside the inner member of a sequence.
     */
    if (ctx->phase == 2) {
      asn_dec_rval_t tmprval;
      void *memb_ptr;   /* Pointer to the member */
      void **memb_ptr2; /* Pointer to that pointer */

      elm = &td->elements[edx];

      if (elm->flags & ATF_POINTER) {
        /* Member is a pointer to another structure */
        memb_ptr2 = (void **)((char *)st + elm->memb_offset);
      } else {
        memb_ptr = (char *)st + elm->memb_offset;
        memb_ptr2 = &memb_ptr;
      }

      /* Invoke the inner type decoder, m.b. multiple times */
      tmprval = elm->type->xer_decoder(opt_codec_ctx, elm->type, memb_ptr2,
                                       elm->name, buf_ptr, size);
      XER_ADVANCE(tmprval.consumed);
      if (tmprval.code != RC_OK) RETURN(tmprval.code);
      ctx->phase = 1; /* Back to body processing */
      ctx->step = ++edx;
      ASN_DEBUG("XER/SEQUENCE phase => %d, step => %d", ctx->phase, ctx->step);
      /* Fall through */
    }

    /*
     * Get the next part of the XML stream.
     */
    ch_size = xer_next_token(&ctx->context, buf_ptr, size, &ch_type);
    switch (ch_size) {
      case -1:
        RETURN(RC_FAIL);
      case 0:
        RETURN(RC_WMORE);
      default:
        switch (ch_type) {
          case PXER_COMMENT:      /* Got XML comment */
          case PXER_TEXT:         /* Ignore free-standing text */
            XER_ADVANCE(ch_size); /* Skip silently */
            continue;
          case PXER_TAG:
            break; /* Check the rest down there */
        }
    }

    tcv = xer_check_tag(buf_ptr, ch_size, xml_tag);
    ASN_DEBUG("XER/SEQUENCE: tcv = %d, ph=%d [%s]", tcv, ctx->phase, xml_tag);

    /* Skip the extensions section */
    if (ctx->phase == 3) {
      switch (xer_skip_unknown(tcv, &ctx->left)) {
        case -1:
          ctx->phase = 4;
          RETURN(RC_FAIL);
        case 0:
          XER_ADVANCE(ch_size);
          continue;
        case 1:
          XER_ADVANCE(ch_size);
          ctx->phase = 1;
          continue;
        case 2:
          ctx->phase = 1;
          break;
      }
    }

    switch (tcv) {
      case XCT_CLOSING:
        if (ctx->phase == 0) break;
        ctx->phase = 0;
        /* Fall through */
      case XCT_BOTH:
        if (ctx->phase == 0) {
          if (edx >= td->elements_count ||
              /* Explicit OPTIONAL specs reaches the end */
              (edx + elements[edx].optional == td->elements_count) ||
              /* All extensions are optional */
              (IN_EXTENSION_GROUP(specs, edx) &&
               specs->ext_before > td->elements_count)) {
            XER_ADVANCE(ch_size);
            ctx->phase = 4; /* Phase out */
            RETURN(RC_OK);
          } else {
            ASN_DEBUG("Premature end of XER SEQUENCE");
            RETURN(RC_FAIL);
          }
        }
        /* Fall through */
      case XCT_OPENING:
        if (ctx->phase == 0) {
          XER_ADVANCE(ch_size);
          ctx->phase = 1; /* Processing body phase */
          continue;
        }
        /* Fall through */
      case XCT_UNKNOWN_OP:
      case XCT_UNKNOWN_BO:

        ASN_DEBUG("XER/SEQUENCE: tcv=%d, ph=%d, edx=%d", tcv, ctx->phase, edx);
        if (ctx->phase != 1) {
          break; /* Really unexpected */
        }

        if (edx < td->elements_count) {
          /*
           * Search which member corresponds to this tag.
           */
          edx_end = edx + elements[edx].optional + 1;
          if (edx_end > td->elements_count) edx_end = td->elements_count;
          for (n = edx; n < edx_end; n++) {
            elm = &td->elements[n];
            tcv = xer_check_tag(buf_ptr, ch_size, elm->name);
            switch (tcv) {
              case XCT_BOTH:
              case XCT_OPENING:
                /*
                 * Process this member.
                 */
                ctx->step = edx = n;
                ctx->phase = 2;
                break;
              case XCT_UNKNOWN_OP:
              case XCT_UNKNOWN_BO:
                continue;
              default:
                n = edx_end;
                break; /* Phase out */
            }
            break;
          }
          if (n != edx_end) continue;
        } else {
          ASN_DEBUG("Out of defined members: %d/%d", edx, td->elements_count);
        }

        /* It is expected extension */
        if (IN_EXTENSION_GROUP(
                specs, edx + (edx < td->elements_count ? elements[edx].optional
                                                       : 0))) {
          ASN_DEBUG("Got anticipated extension at %d", edx);
          /*
           * Check for (XCT_BOTH or XCT_UNKNOWN_BO)
           * By using a mask. Only record a pure
           * <opening> tags.
           */
          if (tcv & XCT_CLOSING) {
            /* Found </extension> without body */
          } else {
            ctx->left = 1;
            ctx->phase = 3; /* Skip ...'s */
          }
          XER_ADVANCE(ch_size);
          continue;
        }

        /* Fall through */
      default:
        break;
    }

    ASN_DEBUG("Unexpected XML tag in SEQUENCE [%c%c%c%c%c%c]",
              size > 0 ? ((const char *)buf_ptr)[0] : '.',
              size > 1 ? ((const char *)buf_ptr)[1] : '.',
              size > 2 ? ((const char *)buf_ptr)[2] : '.',
              size > 3 ? ((const char *)buf_ptr)[3] : '.',
              size > 4 ? ((const char *)buf_ptr)[4] : '.',
              size > 5 ? ((const char *)buf_ptr)[5] : '.');
    break;
  }

  ctx->phase = 4; /* "Phase out" on hard failure */
  RETURN(RC_FAIL);
}

asn_enc_rval_t SEQUENCE_encode_xer(asn_TYPE_descriptor_t *td, void *sptr,
                                   int ilevel, enum xer_encoder_flags_e flags,
                                   asn_app_consume_bytes_f *cb, void *app_key) {
  asn_enc_rval_t er;
  int xcan = (flags & XER_F_CANONICAL);
  int edx;

  if (!sptr) _ASN_ENCODE_FAILED;

  er.encoded = 0;

  for (edx = 0; edx < td->elements_count; edx++) {
    asn_enc_rval_t tmper;
    asn_TYPE_member_t *elm = &td->elements[edx];
    void *memb_ptr;
    const char *mname = elm->name;
    unsigned int mlen = strlen(mname);

    if (elm->flags & ATF_POINTER) {
      memb_ptr = *(void **)((char *)sptr + elm->memb_offset);
      if (!memb_ptr) {
        if (elm->optional) continue;
        /* Mandatory element is missing */
        _ASN_ENCODE_FAILED;
      }
    } else {
      memb_ptr = (void *)((char *)sptr + elm->memb_offset);
    }

    if (!xcan) _i_ASN_TEXT_INDENT(1, ilevel);
    _ASN_CALLBACK3("<", 1, mname, mlen, ">", 1);

    /* Print the member itself */
    tmper = elm->type->xer_encoder(elm->type, memb_ptr, ilevel + 1, flags, cb,
                                   app_key);
    if (tmper.encoded == -1) return tmper;

    _ASN_CALLBACK3("</", 2, mname, mlen, ">", 1);
    er.encoded += 5 + (2 * mlen) + tmper.encoded;
  }

  if (!xcan) _i_ASN_TEXT_INDENT(1, ilevel - 1);

  _ASN_ENCODED_OK(er);
cb_failed:
  _ASN_ENCODE_FAILED;
}

int SEQUENCE_print(asn_TYPE_descriptor_t *td, const void *sptr, int ilevel,
                   asn_app_consume_bytes_f *cb, void *app_key) {
  int edx;
  int ret;

  if (!sptr) return (cb("<absent>", 8, app_key) < 0) ? -1 : 0;

  /* Dump preamble */
  if (cb(td->name, strlen(td->name), app_key) < 0 ||
      cb(" ::= {", 6, app_key) < 0)
    return -1;

  for (edx = 0; edx < td->elements_count; edx++) {
    asn_TYPE_member_t *elm = &td->elements[edx];
    const void *memb_ptr;

    if (elm->flags & ATF_POINTER) {
      memb_ptr = *(const void *const *)((const char *)sptr + elm->memb_offset);
      if (!memb_ptr) {
        if (elm->optional) continue;
        /* Print <absent> line */
        /* Fall through */
      }
    } else {
      memb_ptr = (const void *)((const char *)sptr + elm->memb_offset);
    }

    /* Indentation */
    _i_INDENT(1);

    /* Print the member's name and stuff */
    if (cb(elm->name, strlen(elm->name), app_key) < 0 ||
        cb(": ", 2, app_key) < 0)
      return -1;

    /* Print the member itself */
    ret = elm->type->print_struct(elm->type, memb_ptr, ilevel + 1, cb, app_key);
    if (ret) return ret;
  }

  ilevel--;
  _i_INDENT(1);

  return (cb("}", 1, app_key) < 0) ? -1 : 0;
}

void SEQUENCE_free(asn_TYPE_descriptor_t *td, void *sptr, int contents_only) {
  int edx;

  if (!td || !sptr) return;

  ASN_DEBUG("Freeing %s as SEQUENCE", td->name);

  for (edx = 0; edx < td->elements_count; edx++) {
    asn_TYPE_member_t *elm = &td->elements[edx];
    void *memb_ptr;
    if (elm->flags & ATF_POINTER) {
      memb_ptr = *(void **)((char *)sptr + elm->memb_offset);
      if (memb_ptr) ASN_STRUCT_FREE(*elm->type, memb_ptr);
    } else {
      memb_ptr = (void *)((char *)sptr + elm->memb_offset);
      ASN_STRUCT_FREE_CONTENTS_ONLY(*elm->type, memb_ptr);
    }
  }

  if (!contents_only) {
    FREEMEM(sptr);
  }
}

int SEQUENCE_constraint(asn_TYPE_descriptor_t *td, const void *sptr,
                        asn_app_constraint_failed_f *ctfailcb, void *app_key) {
  int edx;

  if (!sptr) {
    _ASN_CTFAIL(app_key, td, sptr, "%s: value not given (%s:%d)", td->name,
                __FILE__, __LINE__);
    return -1;
  }

  /*
   * Iterate over structure members and check their validity.
   */
  for (edx = 0; edx < td->elements_count; edx++) {
    asn_TYPE_member_t *elm = &td->elements[edx];
    const void *memb_ptr;

    if (elm->flags & ATF_POINTER) {
      memb_ptr = *(const void *const *)((const char *)sptr + elm->memb_offset);
      if (!memb_ptr) {
        if (elm->optional) continue;
        _ASN_CTFAIL(app_key, td, sptr,
                    "%s: mandatory element %s absent (%s:%d)", td->name,
                    elm->name, __FILE__, __LINE__);
        return -1;
      }
    } else {
      memb_ptr = (const void *)((const char *)sptr + elm->memb_offset);
    }

    if (elm->memb_constraints) {
      int ret = elm->memb_constraints(elm->type, memb_ptr, ctfailcb, app_key);
      if (ret) return ret;
    } else {
      int ret =
          elm->type->check_constraints(elm->type, memb_ptr, ctfailcb, app_key);
      if (ret) return ret;
      /*
       * Cannot inherit it earlier:
       * need to make sure we get the updated version.
       */
      elm->memb_constraints = elm->type->check_constraints;
    }
  }

  return 0;
}

asn_dec_rval_t SEQUENCE_decode_uper(asn_codec_ctx_t *opt_codec_ctx,
                                    asn_TYPE_descriptor_t *td,
                                    asn_per_constraints_t *constraints,
                                    void **sptr, asn_per_data_t *pd) {
  asn_SEQUENCE_specifics_t *specs = (asn_SEQUENCE_specifics_t *)td->specifics;
  void *st = *sptr; /* Target structure. */
  int extpresent;   /* Extension additions are present */
  uint8_t *opres;   /* Presence of optional root members */
  asn_per_data_t opmd;
  asn_dec_rval_t rv;
  int edx;

  (void)constraints;

  if (_ASN_STACK_OVERFLOW_CHECK(opt_codec_ctx)) _ASN_DECODE_FAILED;

  if (!st) {
    st = *sptr = CALLOC(1, specs->struct_size);
    if (!st) _ASN_DECODE_FAILED;
  }

  ASN_DEBUG("Decoding %s as SEQUENCE (UPER)", td->name);

  /* Handle extensions */
  if (specs->ext_before >= 0) {
    extpresent = per_get_few_bits(pd, 1);
    if (extpresent < 0) _ASN_DECODE_STARVED;
  } else {
    extpresent = 0;
  }

  /* Prepare a place and read-in the presence bitmap */
  memset(&opmd, 0, sizeof(opmd));
  if (specs->roms_count) {
    opres = (uint8_t *)MALLOC(((specs->roms_count + 7) >> 3) + 1);
    if (!opres) _ASN_DECODE_FAILED;
    /* Get the presence map */
    if (per_get_many_bits(pd, opres, 0, specs->roms_count)) {
      FREEMEM(opres);
      _ASN_DECODE_STARVED;
    }
    opmd.buffer = opres;
    opmd.nbits = specs->roms_count;
    ASN_DEBUG("Read in presence bitmap for %s of %d bits (%x..)", td->name,
              specs->roms_count, *opres);
  } else {
    opres = 0;
  }

  /*
   * Get the sequence ROOT elements.
   */
  for (edx = 0; edx < td->elements_count; edx++) {
    asn_TYPE_member_t *elm = &td->elements[edx];
    void *memb_ptr;   /* Pointer to the member */
    void **memb_ptr2; /* Pointer to that pointer */

    if (IN_EXTENSION_GROUP(specs, edx)) continue;

    /* Fetch the pointer to this member */
    if (elm->flags & ATF_POINTER) {
      memb_ptr2 = (void **)((char *)st + elm->memb_offset);
    } else {
      memb_ptr = (char *)st + elm->memb_offset;
      memb_ptr2 = &memb_ptr;
    }

    /* Deal with optionality */
    if (elm->optional) {
      int present = per_get_few_bits(&opmd, 1);
      ASN_DEBUG("Member %s->%s is optional, p=%d (%d->%d)", td->name, elm->name,
                present, (int)opmd.nboff, (int)opmd.nbits);
      if (present == 0) {
        /* This element is not present */
        if (elm->default_value) {
          /* Fill-in DEFAULT */
          if (elm->default_value(1, memb_ptr2)) {
            FREEMEM(opres);
            _ASN_DECODE_FAILED;
          }
          ASN_DEBUG("Filled-in default");
        }
        /* The member is just not present */
        continue;
      }
      /* Fall through */
    }

    /* Fetch the member from the stream */
    ASN_DEBUG("Decoding member %s in %s", elm->name, td->name);
    rv = elm->type->uper_decoder(opt_codec_ctx, elm->type, elm->per_constraints,
                                 memb_ptr2, pd);
    if (rv.code != RC_OK) {
      ASN_DEBUG("Failed decode %s in %s", elm->name, td->name);
      FREEMEM(opres);
      return rv;
    }
  }

  /* Optionality map is not needed anymore */
  FREEMEM(opres);

  /*
   * Deal with extensions.
   */
  if (extpresent) {
    ssize_t bmlength;
    uint8_t *epres; /* Presence of extension members */
    asn_per_data_t epmd;

    bmlength = uper_get_nslength(pd);
    if (bmlength < 0) _ASN_DECODE_STARVED;

    ASN_DEBUG("Extensions %ld present in %s", (long)bmlength, td->name);

    epres = (uint8_t *)MALLOC((bmlength + 15) >> 3);
    if (!epres) _ASN_DECODE_STARVED;

    /* Get the extensions map */
    if (per_get_many_bits(pd, epres, 0, bmlength)) _ASN_DECODE_STARVED;

    memset(&epmd, 0, sizeof(epmd));
    epmd.buffer = epres;
    epmd.nbits = bmlength;
    ASN_DEBUG("Read in extensions bitmap for %s of %d bits (%x..)", td->name,
              bmlength, *epres);

    /* Go over extensions and read them in */
    for (edx = specs->ext_after + 1; edx < td->elements_count; edx++) {
      asn_TYPE_member_t *elm = &td->elements[edx];
      void *memb_ptr;   /* Pointer to the member */
      void **memb_ptr2; /* Pointer to that pointer */
      int present;

      if (!IN_EXTENSION_GROUP(specs, edx)) {
        ASN_DEBUG("%d is not extension", edx);
        continue;
      }

      /* Fetch the pointer to this member */
      if (elm->flags & ATF_POINTER) {
        memb_ptr2 = (void **)((char *)st + elm->memb_offset);
      } else {
        memb_ptr = (void *)((char *)st + elm->memb_offset);
        memb_ptr2 = &memb_ptr;
      }

      present = per_get_few_bits(&epmd, 1);
      if (present <= 0) {
        if (present < 0) break; /* No more extensions */
        continue;
      }

      ASN_DEBUG("Decoding member %s in %s %p", elm->name, td->name, *memb_ptr2);
      rv = uper_open_type_get(opt_codec_ctx, elm->type, elm->per_constraints,
                              memb_ptr2, pd);
      if (rv.code != RC_OK) {
        FREEMEM(epres);
        return rv;
      }
    }

    /* Skip over overflow extensions which aren't present
     * in this system's version of the protocol */
    for (;;) {
      ASN_DEBUG("Getting overflow extensions");
      switch (per_get_few_bits(&epmd, 1)) {
        case -1:
          break;
        case 0:
          continue;
        default:
          if (uper_open_type_skip(opt_codec_ctx, pd)) {
            FREEMEM(epres);
            _ASN_DECODE_STARVED;
          }
      }
      break;
    }

    FREEMEM(epres);
  }

  /* Fill DEFAULT members in extensions */
  for (edx = specs->roms_count; edx < specs->roms_count + specs->aoms_count;
       edx++) {
    asn_TYPE_member_t *elm = &td->elements[edx];
    void **memb_ptr2; /* Pointer to member pointer */

    if (!elm->default_value) continue;

    /* Fetch the pointer to this member */
    if (elm->flags & ATF_POINTER) {
      memb_ptr2 = (void **)((char *)st + elm->memb_offset);
      if (*memb_ptr2) continue;
    } else {
      continue; /* Extensions are all optionals */
    }

    /* Set default value */
    if (elm->default_value(1, memb_ptr2)) {
      _ASN_DECODE_FAILED;
    }
  }

  rv.consumed = 0;
  rv.code = RC_OK;
  return rv;
}

asn_dec_rval_t SEQUENCE_decode_aper(asn_codec_ctx_t *opt_codec_ctx,
                                    asn_TYPE_descriptor_t *td,
                                    asn_per_constraints_t *constraints,
                                    void **sptr, asn_per_data_t *pd) {
  asn_SEQUENCE_specifics_t *specs = (asn_SEQUENCE_specifics_t *)td->specifics;
  void *st = *sptr; /* Target structure. */
  int extpresent;   /* Extension additions are present */
  uint8_t *opres;   /* Presence of optional root members */
  asn_per_data_t opmd;
  asn_dec_rval_t rv;
  int edx;

  (void)constraints;

  if (_ASN_STACK_OVERFLOW_CHECK(opt_codec_ctx)) _ASN_DECODE_FAILED;

  if (!st) {
    st = *sptr = CALLOC(1, specs->struct_size);
    if (!st) _ASN_DECODE_FAILED;
  }

  ASN_DEBUG("Decoding %s as SEQUENCE (APER)", td->name);

  /* Handle extensions */
  if (specs->ext_before >= 0) {
    extpresent = per_get_few_bits(pd, 1);
    if (extpresent < 0) _ASN_DECODE_STARVED;
  } else {
    extpresent = 0;
  }

  /* Prepare a place and read-in the presence bitmap */
  memset(&opmd, 0, sizeof(opmd));
  if (specs->roms_count) {
    opres = (uint8_t *)MALLOC(((specs->roms_count + 7) >> 3) + 1);
    if (!opres) _ASN_DECODE_FAILED;
    /* Get the presence map */
    if (per_get_many_bits(pd, opres, 0, specs->roms_count)) {
      FREEMEM(opres);
      _ASN_DECODE_STARVED;
    }
    opmd.buffer = opres;
    opmd.nbits = specs->roms_count;
    ASN_DEBUG("Read in presence bitmap for %s of %d bits (%x..)", td->name,
              specs->roms_count, *opres);
  } else {
    opres = 0;
  }

  /*
   * Get the sequence ROOT elements.
   */
  for (edx = 0; edx < td->elements_count; edx++) {
    asn_TYPE_member_t *elm = &td->elements[edx];
    void *memb_ptr;   /* Pointer to the member */
    void **memb_ptr2; /* Pointer to that pointer */

    if (IN_EXTENSION_GROUP(specs, edx)) continue;

    /* Fetch the pointer to this member */
    if (elm->flags & ATF_POINTER) {
      memb_ptr2 = (void **)((char *)st + elm->memb_offset);
    } else {
      memb_ptr = (char *)st + elm->memb_offset;
      memb_ptr2 = &memb_ptr;
    }

    /* Deal with optionality */
    if (elm->optional) {
      int present = per_get_few_bits(&opmd, 1);
      ASN_DEBUG("Member %s->%s is optional, p=%d (%d->%d)", td->name, elm->name,
                present, (int)opmd.nboff, (int)opmd.nbits);
      if (present == 0) {
        /* This element is not present */
        if (elm->default_value) {
          /* Fill-in DEFAULT */
          if (elm->default_value(1, memb_ptr2)) {
            FREEMEM(opres);
            _ASN_DECODE_FAILED;
          }
          ASN_DEBUG("Filled-in default");
        }
        /* The member is just not present */
        continue;
      }
      /* Fall through */
    }

    /* Fetch the member from the stream */
    ASN_DEBUG("Decoding member %s in %s", elm->name, td->name);
    rv = elm->type->aper_decoder(opt_codec_ctx, elm->type, elm->per_constraints,
                                 memb_ptr2, pd);
    if (rv.code != RC_OK) {
      ASN_DEBUG("Failed decode %s in %s", elm->name, td->name);
      FREEMEM(opres);
      return rv;
    }
  }

  /* Optionality map is not needed anymore */
  FREEMEM(opres);

  /*
   * Deal with extensions.
   */
  if (extpresent) {
    ssize_t bmlength;
    uint8_t *epres; /* Presence of extension members */
    asn_per_data_t epmd;

    bmlength = uper_get_nslength(pd);
    if (bmlength < 0) _ASN_DECODE_STARVED;

    ASN_DEBUG("Extensions %d present in %s", bmlength, td->name);

    epres = (uint8_t *)MALLOC((bmlength + 15) >> 3);
    if (!epres) _ASN_DECODE_STARVED;

    /* Get the extensions map */
    if (per_get_many_bits(pd, epres, 0, bmlength)) _ASN_DECODE_STARVED;

    memset(&epmd, 0, sizeof(epmd));
    epmd.buffer = epres;
    epmd.nbits = bmlength;
    ASN_DEBUG("Read in extensions bitmap for %s of %ld bits (%x..)", td->name,
              (long)bmlength, *epres);

    /* Go over extensions and read them in */
    for (edx = specs->ext_after + 1; edx < td->elements_count; edx++) {
      asn_TYPE_member_t *elm = &td->elements[edx];
      void *memb_ptr;   /* Pointer to the member */
      void **memb_ptr2; /* Pointer to that pointer */
      int present;

      if (!IN_EXTENSION_GROUP(specs, edx)) {
        ASN_DEBUG("%d is not extension", edx);
        continue;
      }

      /* Fetch the pointer to this member */
      if (elm->flags & ATF_POINTER) {
        memb_ptr2 = (void **)((char *)st + elm->memb_offset);
      } else {
        memb_ptr = (void *)((char *)st + elm->memb_offset);
        memb_ptr2 = &memb_ptr;
      }

      present = per_get_few_bits(&epmd, 1);
      if (present <= 0) {
        if (present < 0) break; /* No more extensions */
        continue;
      }

      ASN_DEBUG("Decoding member %s in %s %p", elm->name, td->name, *memb_ptr2);
      rv = uper_open_type_get(opt_codec_ctx, elm->type, elm->per_constraints,
                              memb_ptr2, pd);
      if (rv.code != RC_OK) {
        FREEMEM(epres);
        return rv;
      }
    }

    /* Skip over overflow extensions which aren't present
     * in this system's version of the protocol */
    for (;;) {
      ASN_DEBUG("Getting overflow extensions");
      switch (per_get_few_bits(&epmd, 1)) {
        case -1:
          break;
        case 0:
          continue;
        default:
          if (uper_open_type_skip(opt_codec_ctx, pd)) {
            FREEMEM(epres);
            _ASN_DECODE_STARVED;
          }
      }
      break;
    }

    FREEMEM(epres);
  }

  /* Fill DEFAULT members in extensions */
  for (edx = specs->roms_count; edx < specs->roms_count + specs->aoms_count;
       edx++) {
    asn_TYPE_member_t *elm = &td->elements[edx];
    void **memb_ptr2; /* Pointer to member pointer */

    if (!elm->default_value) continue;

    /* Fetch the pointer to this member */
    if (elm->flags & ATF_POINTER) {
      memb_ptr2 = (void **)((char *)st + elm->memb_offset);
      if (*memb_ptr2) continue;
    } else {
      continue; /* Extensions are all optionals */
    }

    /* Set default value */
    if (elm->default_value(1, memb_ptr2)) {
      _ASN_DECODE_FAILED;
    }
  }

  rv.consumed = 0;
  rv.code = RC_OK;
  return rv;
}

static int SEQUENCE_handle_extensions(asn_TYPE_descriptor_t *td, void *sptr,
                                      asn_per_outp_t *po1,
                                      asn_per_outp_t *po2) {
  asn_SEQUENCE_specifics_t *specs = (asn_SEQUENCE_specifics_t *)td->specifics;
  int exts_present = 0;
  int exts_count = 0;
  int edx;

  if (specs->ext_before < 0) return 0;

  /* Find out which extensions are present */
  for (edx = specs->ext_after + 1; edx < td->elements_count; edx++) {
    asn_TYPE_member_t *elm = &td->elements[edx];
    void *memb_ptr;   /* Pointer to the member */
    void **memb_ptr2; /* Pointer to that pointer */
    int present;

    if (!IN_EXTENSION_GROUP(specs, edx)) {
      ASN_DEBUG("%s (@%d) is not extension", elm->type->name, edx);
      continue;
    }

    /* Fetch the pointer to this member */
    if (elm->flags & ATF_POINTER) {
      memb_ptr2 = (void **)((char *)sptr + elm->memb_offset);
      present = (*memb_ptr2 != 0);
    } else {
      memb_ptr = (void *)((char *)sptr + elm->memb_offset);
      memb_ptr2 = &memb_ptr;
      present = 1;
    }

    ASN_DEBUG("checking %s (@%d) present => %d", elm->type->name, edx, present);
    exts_count++;
    exts_present += present;

    /* Encode as presence marker */
    if (po1 && per_put_few_bits(po1, present, 1)) return -1;
    /* Encode as open type field */
    if (po2 && present &&
        uper_open_type_put(elm->type, elm->per_constraints, *memb_ptr2, po2))
      return -1;
  }

  return exts_present ? exts_count : 0;
}

asn_enc_rval_t SEQUENCE_encode_uper(asn_TYPE_descriptor_t *td,
                                    asn_per_constraints_t *constraints,
                                    void *sptr, asn_per_outp_t *po) {
  asn_SEQUENCE_specifics_t *specs = (asn_SEQUENCE_specifics_t *)td->specifics;
  asn_enc_rval_t er;
  int n_extensions;
  int edx;
  int i;

  (void)constraints;

  if (!sptr) _ASN_ENCODE_FAILED;

  er.encoded = 0;

  ASN_DEBUG("Encoding %s as SEQUENCE (UPER)", td->name);

  /*
   * X.691#18.1 Whether structure is extensible
   * and whether to encode extensions
   */
  if (specs->ext_before >= 0) {
    n_extensions = SEQUENCE_handle_extensions(td, sptr, 0, 0);
    per_put_few_bits(po, n_extensions ? 1 : 0, 1);
  } else {
    n_extensions = 0; /* There are no extensions to encode */
  }

  /* Encode a presence bitmap */
  for (i = 0; i < specs->roms_count; i++) {
    asn_TYPE_member_t *elm;
    void *memb_ptr;   /* Pointer to the member */
    void **memb_ptr2; /* Pointer to that pointer */
    int present;

    edx = specs->oms[i];
    elm = &td->elements[edx];

    /* Fetch the pointer to this member */
    if (elm->flags & ATF_POINTER) {
      memb_ptr2 = (void **)((char *)sptr + elm->memb_offset);
      present = (*memb_ptr2 != 0);
    } else {
      memb_ptr = (void *)((char *)sptr + elm->memb_offset);
      memb_ptr2 = &memb_ptr;
      present = 1;
    }

    /* Eliminate default values */
    if (present && elm->default_value && elm->default_value(0, memb_ptr2) == 1)
      present = 0;

    ASN_DEBUG("Element %s %s %s->%s is %s",
              elm->flags & ATF_POINTER ? "ptr" : "inline",
              elm->default_value ? "def" : "wtv", td->name, elm->name,
              present ? "present" : "absent");
    if (per_put_few_bits(po, present, 1)) _ASN_ENCODE_FAILED;
  }

  /*
   * Encode the sequence ROOT elements.
   */
  ASN_DEBUG("ext_after = %d, ec = %d, eb = %d", specs->ext_after,
            td->elements_count, specs->ext_before);
  for (edx = 0; edx < ((specs->ext_after < 0) ? td->elements_count
                                              : specs->ext_before - 1);
       edx++) {
    asn_TYPE_member_t *elm = &td->elements[edx];
    void *memb_ptr;   /* Pointer to the member */
    void **memb_ptr2; /* Pointer to that pointer */

    if (IN_EXTENSION_GROUP(specs, edx)) continue;

    ASN_DEBUG("About to encode %s", elm->type->name);

    /* Fetch the pointer to this member */
    if (elm->flags & ATF_POINTER) {
      memb_ptr2 = (void **)((char *)sptr + elm->memb_offset);
      if (!*memb_ptr2) {
        ASN_DEBUG("Element %s %d not present", elm->name, edx);
        if (elm->optional) continue;
        /* Mandatory element is missing */
        _ASN_ENCODE_FAILED;
      }
    } else {
      memb_ptr = (void *)((char *)sptr + elm->memb_offset);
      memb_ptr2 = &memb_ptr;
    }

    /* Eliminate default values */
    if (elm->default_value && elm->default_value(0, memb_ptr2) == 1) continue;

    ASN_DEBUG("Encoding %s->%s", td->name, elm->name);
    er = elm->type->uper_encoder(elm->type, elm->per_constraints, *memb_ptr2,
                                 po);
    if (er.encoded == -1) return er;
  }

  /* No extensions to encode */
  if (!n_extensions) _ASN_ENCODED_OK(er);

  ASN_DEBUG("Length of %d bit-map", n_extensions);
  /* #18.8. Write down the presence bit-map length. */
  if (uper_put_nslength(po, n_extensions)) _ASN_ENCODE_FAILED;

  ASN_DEBUG("Bit-map of %d elements", n_extensions);
  /* #18.7. Encoding the extensions presence bit-map. */
  /* TODO: act upon NOTE in #18.7 for canonical PER */
  if (SEQUENCE_handle_extensions(td, sptr, po, 0) != n_extensions)
    _ASN_ENCODE_FAILED;

  ASN_DEBUG("Writing %d extensions", n_extensions);
  /* #18.9. Encode extensions as open type fields. */
  if (SEQUENCE_handle_extensions(td, sptr, 0, po) != n_extensions)
    _ASN_ENCODE_FAILED;

  _ASN_ENCODED_OK(er);
}

asn_enc_rval_t SEQUENCE_encode_aper(asn_TYPE_descriptor_t *td,
                                    asn_per_constraints_t *constraints,
                                    void *sptr, asn_per_outp_t *po) {
  asn_SEQUENCE_specifics_t *specs = (asn_SEQUENCE_specifics_t *)td->specifics;
  asn_enc_rval_t er;
  int n_extensions;
  int edx;
  int i;

  (void)constraints;

  if (!sptr) _ASN_ENCODE_FAILED;

  er.encoded = 0;

  ASN_DEBUG("Encoding %s as SEQUENCE (APER)", td->name);

  /*
   * X.691#18.1 Whether structure is extensible
   * and whether to encode extensions
   */
  if (specs->ext_before >= 0) {
    n_extensions = SEQUENCE_handle_extensions(td, sptr, 0, 0);
    per_put_few_bits(po, n_extensions ? 1 : 0, 1);
  } else {
    n_extensions = 0; /* There are no extensions to encode */
  }

  /* Encode a presence bitmap */
  for (i = 0; i < specs->roms_count; i++) {
    asn_TYPE_member_t *elm;
    void *memb_ptr;   /* Pointer to the member */
    void **memb_ptr2; /* Pointer to that pointer */
    int present;

    edx = specs->oms[i];
    elm = &td->elements[edx];

    /* Fetch the pointer to this member */
    if (elm->flags & ATF_POINTER) {
      memb_ptr2 = (void **)((char *)sptr + elm->memb_offset);
      present = (*memb_ptr2 != 0);
    } else {
      memb_ptr = (void *)((char *)sptr + elm->memb_offset);
      memb_ptr2 = &memb_ptr;
      present = 1;
    }

    /* Eliminate default values */
    if (present && elm->default_value && elm->default_value(0, memb_ptr2) == 1)
      present = 0;

    ASN_DEBUG("Element %s %s %s->%s is %s",
              elm->flags & ATF_POINTER ? "ptr" : "inline",
              elm->default_value ? "def" : "wtv", td->name, elm->name,
              present ? "present" : "absent");
    if (per_put_few_bits(po, present, 1)) _ASN_ENCODE_FAILED;
  }

  /*
   * Encode the sequence ROOT elements.
   */
  ASN_DEBUG("ext_after = %d, ec = %d, eb = %d", specs->ext_after,
            td->elements_count, specs->ext_before);
  for (edx = 0; edx < ((specs->ext_after < 0) ? td->elements_count
                                              : specs->ext_before - 1);
       edx++) {
    asn_TYPE_member_t *elm = &td->elements[edx];
    void *memb_ptr;   /* Pointer to the member */
    void **memb_ptr2; /* Pointer to that pointer */

    if (IN_EXTENSION_GROUP(specs, edx)) continue;

    ASN_DEBUG("About to encode %s", elm->type->name);

    /* Fetch the pointer to this member */
    if (elm->flags & ATF_POINTER) {
      memb_ptr2 = (void **)((char *)sptr + elm->memb_offset);
      if (!*memb_ptr2) {
        ASN_DEBUG("Element %s %d not present", elm->name, edx);
        if (elm->optional) continue;
        /* Mandatory element is missing */
        _ASN_ENCODE_FAILED;
      }
    } else {
      memb_ptr = (void *)((char *)sptr + elm->memb_offset);
      memb_ptr2 = &memb_ptr;
    }

    /* Eliminate default values */
    if (elm->default_value && elm->default_value(0, memb_ptr2) == 1) continue;

    ASN_DEBUG("Encoding %s->%s", td->name, elm->name);
    er = elm->type->aper_encoder(elm->type, elm->per_constraints, *memb_ptr2,
                                 po);
    if (er.encoded == -1) return er;
  }

  /* No extensions to encode */
  if (!n_extensions) _ASN_ENCODED_OK(er);

  ASN_DEBUG("Length of %d bit-map", n_extensions);
  /* #18.8. Write down the presence bit-map length. */
  if (aper_put_nslength(po, n_extensions)) _ASN_ENCODE_FAILED;

  ASN_DEBUG("Bit-map of %d elements", n_extensions);
  /* #18.7. Encoding the extensions presence bit-map. */
  /* TODO: act upon NOTE in #18.7 for canonical PER */
  if (SEQUENCE_handle_extensions(td, sptr, po, 0) != n_extensions)
    _ASN_ENCODE_FAILED;

  ASN_DEBUG("Writing %d extensions", n_extensions);
  /* #18.9. Encode extensions as open type fields. */
  if (SEQUENCE_handle_extensions(td, sptr, 0, po) != n_extensions)
    _ASN_ENCODE_FAILED;

  _ASN_ENCODED_OK(er);
}

asn_comp_rval_t *SEQUENCE_compare(asn_TYPE_descriptor_t *td1, const void *sptr1,
                                  asn_TYPE_descriptor_t *td2,
                                  const void *sptr2) {
  int edx;
  asn_comp_rval_t *res = NULL;
  asn_comp_rval_t *res2 = NULL;

  COMPARE_CHECK_ARGS(td1, td2, sptr1, sptr2, res)

  if (td1->elements_count != td2->elements_count) {
    res = calloc(1, sizeof(asn_comp_rval_t));
    res->name = td1->name;
    res->structure1 = sptr1;
    res->structure2 = sptr2;
    res->err_code = COMPARE_ERR_CODE_COLLECTION_NUM_ELEMENTS;
    return res;
  }

  for (edx = 0; edx < td1->elements_count; edx++) {
    asn_TYPE_member_t *elm1 = &td1->elements[edx];
    asn_TYPE_member_t *elm2 = &td1->elements[edx];
    const void *memb_ptr1;
    const void *memb_ptr2;

    if (elm1->flags & ATF_POINTER) {
      memb_ptr1 =
          *(const void *const *)((const char *)sptr1 + elm1->memb_offset);
      memb_ptr2 =
          *(const void *const *)((const char *)sptr2 + elm2->memb_offset);
      if ((!memb_ptr1) && (!memb_ptr2)) {
        if (elm1->optional) continue;
      }
      if ((!memb_ptr1) || (!memb_ptr2)) {
        res2 = calloc(1, sizeof(asn_comp_rval_t));
        res2->name = elm1->name;
        res2->structure1 = memb_ptr1;
        res2->structure2 = memb_ptr2;
        res->err_code = COMPARE_ERR_CODE_VALUE_NULL;
        if (NULL == res) {
          res = res2;
        } else {
          res2->next = res;
          res = res2;
        }
        res2 = NULL;
      }
    } else {
      memb_ptr1 = (const void *)((const char *)sptr1 + elm1->memb_offset);
      memb_ptr2 = (const void *)((const char *)sptr2 + elm2->memb_offset);
    }

    /* Compare the member itself */
    res2 = elm1->type->compare(elm1->type, memb_ptr1, elm2->type, memb_ptr2);
    if (res2) {
      if (NULL == res) {
        res = res2;
      } else {
        res2->next = res;
        res = res2;
      }
      res2 = NULL;
    }
  }
  return res;
}
